The truth about traffic

The causes and effects of increasing traffic and congestion are surrounded by myths and misconceptions, according to findings presented in a recent book discussed by Huw Morris.

What do computer, typewriter and traffic have in common? Bizarre as it might seem, they are words whose meaning has changed radically over time. When they first entered the lexicon, "computer" and "typewriter" were occupations.

As for "traffic", it originally had a positive connotation, referring to trade and the movement of goods. Over time, its meaning has become more abstract and interwoven people with vehicles, to the point where no-one is sure what they mean by "heavy traffic". Are we referring to too many people, too many vehicles or too few roads?

Now consider the people who are responsible for all that traffic. It is a disquieting truth that everyone thinks that they are a much better driver than they are in reality. Another uncomfortable fact is that we wrongly label car crashes as accidents. The number one cause of crashes and therefore road deaths is driver failure. Very rarely does anything occur "accidentally".

The problem is that modern-day cars are designed to make drivers feel that they are in a cocoon cut off from the outside world. This sense of anonymity leads to a loss of caution or attention. It can increase aggression on the part of drivers and hence the speed at which they are travelling. At more than 20mph, our judgement, reactions and senses are imperfect. People cannot make eye contact, for example.

All this makes drivers dangerously selfish and deluded. Most crashes happen comparatively close to home because a familiar setting lulls drivers into letting their mental guard down. People who drive convertibles are the safest because they are more likely to be seen by others.

These are not provocative statements but the results of countless scientific, psychological and statistical studies pulled together by Tom Vanderbilt in a new book that considers traffic and our behaviour behind the wheel. Although written from a US viewpoint, the book is crammed with lessons for anyone involved in transport, planning and the built environment. Almost every page includes a stop-in-your-tracks fact or statistic.

Congestion has been a problem for thousands of years. Julius Caesar even ordered a daytime ban on carts and chariots except for those shifting construction materials to temples. Since then, as Vanderbilt points out, cities have grown, demanding more and more ways for people to move around and making the concept of traffic more complicated.

However far cities have expanded, people's daily commuting time around the world remains roughly the same at 1.1 hours. Road rage and speeding is nothing new. In 1720, "furiously driven" carts were the leading cause of death in London, beating fire and "immoderate quaffing". In the New York of 1867, horses killed four pedestrians a week, more than today's fatality rates.

Social patterns reflect car's dominance

Traffic influences almost everything we do. Around 22 per cent of all restaurant meals in the USA are ordered through a car window, while in Northern Ireland one in eight people eat in the car at least once a week. The number of meals consumed in a vehicle across the USA and Europe combined is expected to rise from 73.2 billion in 2003 to 84.4 billion by the end of this year.

The market for audiobooks, unheard of before the late 1980s, is now $871 million a year in the USA. Indeed, Americans spend so much time in their cars that there is a higher incidence of skin cancer on their left sides. The opposite statistic can be quoted in countries where people drive on the left.

Vanderbilt points out that it took mankind centuries to improve on the horse by inventing the railway and then only another few decades to come up with the car. Today, a Ferrari has the equivalent power of 500 horses and it is hurtling down the road in the hands of someone who thinks they are an above-average driver, a recognised psychological phenomenon.

"In study after study, from the USA to France to New Zealand, when groups of drivers were asked to compare themselves to the 'average driver' a majority inevitably responded that they were 'better'," he reports. "This is, of course, statistically improbable and seems like a sketch from Monty Python: 'We are all above average!'"

The book has some shocking revelations about accidents, or rather the lack of them. As the British Medical Journal pointed out in 2001 when it announced that it would no longer use the word, accidents are "often understood to be unpredictable" and therefore unpreventable. But are they?

Vanderbilt reports on DriveCam, a San Diego firm that specialises in recording driver behaviour for organisations from cable installation companies to shuttle buses and taxi firms. A video camera fixed to the rear-view mirror records drivers braking hard or making sudden turns.

The results show that people routinely do things to make crashes "unpreventable". Because they feel in control they lose attention, look out of the window, sing, cry or talk on a mobile phone. Teenagers with passengers are more likely to crash because they drink, dance to music or simply drive more aggressively to impress their fellow travellers.

"Human factors" are behind 90 per cent of all crashes. The slower we drive the quicker we get to our destination. Traffic fatalities are mainly caused by cars crashing into stationary objects and pedestrians. They are rarely caused by slower drivers. Major traffic jams are caused by cars hitting each other because drivers are moving too fast to judge distances accurately.

This brings us to a surprising paradox. Roads are safer if they are more randomly hazardous. Drivers will slow down and pay more attention. Then there is the little matter of warning signs. The hero of the book is the Dutch transport engineer Hans Monderman. He articulated the view that there are two kinds of space - one social and one for traffic - and they are incompatible.

For decades, highway engineers have used signs to such an extent that we now have street clutter. But by using standardised signs, space becomes uniform rather than distinctive. The village road looks similar to the motorway. "Drivers no longer take their cues from the social life of the village. They are working off the signs, which have become such a part of our world that we don't see them any more," says Vanderbilt. Speed bumps do not change drivers' minds either.

Sign removal experiment slowed traffic

Monderman's counterintuitive approach was to remove the signs and make drivers work out any hazards for themselves. In the village of Oudehaske, he stripped out all the signs and redesigned the roads effectively to make pedestrians, motorists and cyclists equal partners, forcing everyone to negotiate on a human level. Each road is 6m wide, making it impossible for two cars to pass each other together with a bicycle.

A month after the project was finished, Monderman took a radar gun and measured the speed of cars passing through the village. Drivers had slowed down so much that he could not get a reading. These principles were also adopted in London's Kensington High Street when road markings, signs and railings were removed. The number of pedestrians killed or seriously injured fell by a massive 60 per cent.

Even the motoring hell that is Los Angeles can be tamed, albeit temporarily. Vanderbilt relates how Los Angeles traffic engineers play God on Oscar night by using a special package on their automated traffic surveillance system to control lights and hence traffic flows across the city to ensure the punctual arrival of 800 limousines at the awards ceremony.

"One engineer pushing one button affects not just one group of people but literally the whole city," he reports. And the winner of that year's best picture? Crash, a film about Los Angeles traffic "on literal and metaphorical levels".

Traffic - Why We Drive the Way We Do and What That Says About Us by Tom Vanderbilt is published by Allen Lane, £20.


- One in ten car crashes in the world are in India.

- The number of cars in Beijing is rising by 1,000 a day.

- The number of Chinese killed on the road every year is now greater than the number of vehicles the country manufactured annually as recently as 1970.

- By 2020, the World Health Organisation predicts that road fatalities will be the planet's third leading cause of death.

- The average American spends 38 hours a year stuck in traffic.

- American roads are underused more than 90 per cent of the time.

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